An ocean heat wave sent temperatures soaring to a new high last year in the Gulf of Maine, continuing an alarming trend in the important marine ecosystem. researchers said Monday.

The surface temperature was more than 4 degrees Fahrenheit above the long-term average and topped the previous record in 2012, according to the Gulf of Maine Research Institute in Portland.

The 2021 average temperature was 54.14 degrees Fahrenheit (12.3 degrees Celsius) compared to the previous record, 53.63 degrees Fahrenheit (12 degrees Celsius) in 2012, the researchers said.

It represents the continuation of a trend.

The rate of warming in the Gulf of Maine has been nearly triple that of the world’s oceans since the early 1980s, researchers said.

David Reidmiller, the institute’s climate center director, said the trend isn’t expected to slow without dramatic efforts to reduce greenhouse gases.

“Going forward, most years are going to be warmer than what we’ve already experienced because of that long-term formula that’s baked in by man-made greenhouse emissions,” he said Monday.

The Gulf of Maine, which stretches from Massachusetts’ Cape Cod to the southern tip of Nova Scotia, has been warming faster than 99% of the world’s oceans in recent years, researchers say. And that's worrisome because the gulf is such an important ecosystem for everything from plankton to rare North American right whales.

The warming waters contribute to sea level rise and have implications for migratory patterns and survival of fish and fowl.

Fishermen have been observing more warm-water fish like black bass migrating northward into New England waters, while lobster populations have crashed in southern New England and Gulf of Maine shrimp populations have been depleted.

Puffin chicks have experienced low survival rates on several Maine islands, something biologists blame on a lack of herring.

But the changes could go beyond what can be seen with the naked eye to include microbes and pathogens that could flourish in warmer waters, bringing about changes that are difficult to predict, Reidmiller said.

Meanwhile, the sea level is growing faster in the Northeast than the global average because of the expanding Gulf Stream and melting polar ice caps and Greenland ice sheets, he said.